The present invention relates to an audio signal processing apparatus, in particular to an audio signal processing apparatus capable of changing the tempo of a musical sound, thereby making it possible to produce various musical sounds having different tones.
Traditionally, there has been known an audio signal processing apparatus called EFFECTOR which can process an audio signal to produce a rhythmical music or a slow tempo music by changing the tempo of an original musical sound. If the audio signal processing apparatus is used in a discotheque, a human operator can operate the apparatus to continuously provide customers (people dancing disco in the discotheque) with more satisfactory musical sound. Further, if the original tempo of a musical sound is changed, it is possible to produce a musical sound having new musical feelings from time to time, to thereby more effectively satisfy the customers dancing in the discotheque.
A conventional audio signal processing apparatus has a tempo adjusting dial which is allowed to be operated by a human operator to adjust the tempo of a musical sound in accordance with his or her own musical feelings.
However, with the above conventional audio signal processing apparatus, since it is necessary for a human operator to adjust the tempo of a musical sound in accordance with his or her own musical feelings, it is difficult for him or her to continuously change or adjust the tempo of a musical sound for a long time, hence making it difficult to produce a truly satisfactory musical sound. Further, since the tempo adjustment is made all by manual operation, a comparatively long time is required until a desired tempo is obtained, thus an operation efficiency is relatively low.
It is an object of the present invention to provide an improved audio signal processing apparatus capable of automatically changing the tempo of a musical sound, thereby ensuring an improved operation efficiency of said audio signal processing apparatus, so as to solve the above-mentioned problems peculiar to the above-discussed prior art.
According to the present invention, there is provided an audio signal processing apparatus capable of changing the tempo of an input audio signal, said apparatus comprising: magnification designating means capable of designating a plurality of different magnifications; means capable of automatically detecting a BPM (Beats Per Minute) or a beat period of the input audio signal, changing said BPM or said beat period in accordance with a magnification designated by the magnification designating means, changing the tempo of the audio signal in accordance with the changed BPM and the changed beat period.
In one aspect of the present invention, manual designating means is provided for designating any optional value serving as a BPM and a beat period.
In another aspect of the present invention, fine adjustment means is provided to effect a fine adjustment on a BPM and a beat period.
In a further aspect of the present invention, indicators are provided to indicate a BPM and a beat period.
In a still further aspect of the present invention, a mixer is provided such that an audio signal generated by changing the tempo of said audio signal may be mixed with said input audio signal, thereby producing a newly formed audio signal.
In one more aspect of the present invention, mixing ratio adjusting means is provided to adjust a mixing ratio when an audio signal generated by changing the tempo of said audio signal is mixed with said input audio signal, thereby producing a newly formed audio signal.
The above objects and features of the present invention will become better understood from the following description with reference to the accompanying drawings.